Grinding graphite



v v Patented July 14, 1931 UNITED STATES PATENT orrlcn G-EORG' HANEK OP,F HANOVER, GERMANY GRINDING onarnrrn Ho Drawing. Application filedHarch'fl, 1928, Serial No.266,444, and in Germany Harold, 1925.

This'invention refers broadly to a method of grinding graphite, and inparticular the purer grades thereof to a flour-like condition and tothereby obtain a purer and more I voluminous and more finelydisintegrated owder than generally obtainable heretofore.

it has been ascertained by tests made with difierent grades ofcommercial graphites that the poorer grades are almost as a rule more 19finely ground than the superior grades ofshould be understood that onlysuch kinds of material are suitable for the purpose, as will admit ofbeing removed'after the fine grinding, and of these water-soluble saltshave been found to be very suitable. Thus or-.

dinary salt or rock-salt have produced very satisfactory results. Incase it should be desired to also remove substances from the graphitewhich are only soluble in acids; salt solutions and the like, suchsubstances may also be added which are not entirely soluble in water,but only in acids, such as low grade potash salts, residues from-theextraction of potash and soda-salts and the like. The grinding up of thegraphite with the salts may be efi'ected in the dry condition, as wellas in the presence of a small amount of water. It should however benoted that only so much 4 water may be added, as will still leave largequantities of the salts undissolved. After the desired degree offineness has been obtained, the salts are removed by water or by theaddition of acids and lixiviation.

By treating according. to this method for instance the species ofgraphites known in the trade by the name of powder-graphite, it has beenfound that, when treated accord ing to this method, a considerably finerdis- .5 tribution of the particles of graphite may still be obtained.'The graphite thus pro- 'duced has been found to be particularly By thegrinding up with salts'the graphites become considerably morevoluminous, so that larger quantities of pyrolusite or. of particles ofartificial pyrolusite than heretofore may be enveloped by such treatedgraphites, as compared with graphites of less fine subdivisio It shouldbe understood that the scope of the invention is not restricted to thespecific details herein recited, but modifications are possible withoutdeviating from the spirit of the invention as defined in the appendedclaims, and that the highly disintegrated graphite which is the product.of this invention is applicable to all the various uses in the arts towhich graphite is usually applied.

I claim v 1. The process of highly disintegrating graphite, whichcomprises grinding up and treating graphite with salts possessingsubstantially the physical and chemical properties'of rock-salts.

2. The process of highly disintegrating graphite, which comprisesintimately grinding graphite with mineral salts possessing substantiallythe physical and chemical character of ordinary salt and of rock-salt.

3. The process of disintegrating graphite,

which consists in intimately grinding graphite with mineral salts of thephysical and chemical character of ordinary salt and of rock-salt andinthe presence of an insulticiency of solvent, and then removing said saltby treatment with a solvent.

4. The process of disintegrating graphite, which consists in grindinggraphite and intimately treating it with ordinary neutral salt andthoroughly agitating it therewith,

and after a sufficient degree of fineness has been obtained, dissolvingthe salt and removing it from the graphite.

5. The process of highly disintegrating graphite, which comprises mostintimately grinding the graphite with sand-like fragments of mineralsalts of the class of ordinary salt and of rock-salt and with aninsufiiciency of solvent, and after the desired fineness is obtainedlixiviating the product and 15 removing the salt.

6, As a new product most highly disintegrated, fluffy, uncolloidalgraphiteoccupying a relatively very large volume as compared with itsweight, and suitable for use for batteries and the like.

- GEORG HANEKOP.

